Improved Photoabsorption in Thin Gallium Arsenide Solar Cells using Light Trapping Techniques
Julia D'Rozario, Steve Polly, Seth Hubbard, George Nelson
Rochester Institute of Technology, Rochester, NY, United States

In this work, increasing the photoabsorption in thin film single junction n-i-p gallium arsenide (GaAs) solar cells has been investigated by applying different light trapping structures. One focus has been to develop a random surface texture that varies in three dimensions to increase light scattering at the back of the cell. The random back surface reflector (BSR) was successfully applied to a 2.25 µm thick GaAs solar cell and resulted in a notable 92% increase in current between 873 nm to 950 nm when compared to the control GaAs solar cell on the substrate without a BSR. Simulations of flat reflectors with a dielectric distributed Bragg reflector (DBR) consisting of MgF2/ZnS show reflection greater than 99% between 750 nm and 900 nm. Combinations between the random BSR and DBR structures will be applied to GaAs solar cells on the sub-µm scale. The overall goal is to apply different light trapping structures in < 500 nm thick GaAs solar cells to achieve high output current as compared to the control GaAs solar cell on a substrate without a BSR.